Conventionally, in a manufacturing line of an absorbent article such as a disposable diaper, as shown in a schematic side view of FIG. 1, an absorbent body 1 that absorbs a liquid such as a waste fluid has been produced. The absorbent body 1 is produced by crushing a pulp sheet 3 with a crusher 20 into pulp fibers 4, and laminating these pulp fibers 4 into a predetermined shape such as a substantially rectangular parallelepiped with a fiber stacking device 30 (PTL 1).